[OSGeo-Discuss] 'lossless' JPEG2000

[Bruce.Bannerman at dpi.vic.gov.au]

IMO:


Michael,

Thanks for the comments on this thread.

I've had a couple of private emails expressing interest in the outcome, so 
I'll continue this conversation in public, rather than moving it offline.


One of the problems that I have is that I understand that JPEG 2000 can be 
'lossy' or 'non-lossy'.

(Is there a way to tell if a JPEG2000 file is lossy or not?)


I don't pretend to understand the maths behind wavelet compressions.

I have also not seen 'proof' that would convince me I would be able to 
safely compress all of my imagery using JPEG2000, (potentially) throw away 
my source imagery and feel confident that I'd be able to run image 
processing routines on the radiometric 'numbers' of the imagery at some 
undefined point in the future with confidence in the integrity of the 
results.

As a reminder, when talking about 'imagery', I'm using the term in its 
broadest sense to include data such as multi and hyperspectral data in the 
umbrella term 'imagery'. I'm not talking about only three bands displayed 
as Red, Green and Blue, but **all** the bands in the 'file'.


The description of a test that I included in the early stages of this 
thread would give me a degree of confidence that JPEG 2000 was a suitable 
format for long term archival of image data.

All that I'm seeing at the moment from many people and organisations is 
something to the effect of "Trust me, your data is saved using a loss-less 
compression."


Bruce




discuss-bounces at lists.osgeo.org wrote on 26/02/2008 04:27:22 AM:

> Bruce-
> 
> Again, I'm not sure how to convince you of this...  JP2 is 
> inherently lossless just like GeoTIFF is; what arguments do you / 
> would you find persuaive to use GeoTIFF?  (alternatively, what do 
> you use now that you trust?)
> 
> [feel free to take this to private email, this is probably a bit 
> esoteric for the rest of the OSGeo crowd]
> 
> -mpg
> 
> 




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